Traffic engineering, which is also known as tele-traffic engineering and traffic management, of a telecommunications network is often used to achieve performance objectives, such as optimization of network resources. Routing capacity and placement of traffic on particular links are examples of network resources for which optimization is often sought. Traffic engineering over Multiprotocol Label Switching (MPLS) enables connection-oriented paths, which provides granular control over packet flow for end-to-end quality assurance. This generally means that a path computed from a source to a destination is subject to a set of constraints, and traffic is forwarded along this computed path. MPLS traffic engineering is a growing implementation in today's service provider networks.
Traffic engineering extensions to Interior Gateway Protocols (IGPs), such as Open Shortest Path First (OSPF) and Intermediate System-Intermediate System (IS-IS) distribute extended link attributes. Resource reservation protocol-traffic engineering (RSVP-TE) provides connection oriented predicted service over a packet network. The Traffic engineering capabilities offered by these protocols may be deemed adequate for Traffic Engineering. However, for a complex network configuration, an administrator specifies explicit routes or paths to forward traffic along these paths. Over a period of time, the routes specified by the administrator may lead to inadequate or unbalanced resource utilization.
On the other hand, constraint-based routing is designed to automatically compute paths subject to a set of constraints. Constraint-based routing assists in performance optimization of operational networks by automatically finding feasible paths that satisfy a set of constraints for traffic trunks. However, constraint-based routing does not provide administrative control to set up explicit paths. As such, in case of a network outage, re-computation of an optimized path is typically unavoidable, inefficient, and causes a performance penalty.